Nitride semiconductors are used in semiconductor light emitting devices, and high performance devices are being put to practical use.
However, when a semiconductor light emitting device is formed by epitaxial growth of a nitride semiconductor crystal on a silicon substrate, which is less expensive and more efficient in manufacturing processes than a sapphire substrate, cracks, defects, etc. may be generated due to the tensile stress included in the epitaxial crystal layer.
When device operation at high current density is required, the temperature of the device becomes high, and cracks, defects, etc. due to the stress caused by thermal expansion may be generated. Such cracks and defects may degrade the device characteristics and in some cases may cause the device break down. It is desired to provide a semiconductor light emitting device with high light emission efficiency which suppresses the degradation in device characteristics and the operational malfunction resulting from the generation of cracks or the introduction of defects due to the tensile stress included in the crystal layer or the stress generated in high temperature operation.